I have a 1999 Polaris 400 L and the sprocket on the driveshaft came off the splined part of the shaft so I hammered it back on but I could not find out how the retainer clip was supposed to hold it on. There seems to be nothing there for it to clip into. Any help would be appreciated. Thanks

 

It should just be a snap ring. Are you sure you have the sprocket all the way on? Should just be a groove on the shaft. Sounds like the sprocket just isn't all the way on, need to get it pushed past the groove so you can set the snap ring.

When you say, it fell off...did it mess up the splines, either on the shaft or sprocket? This might be preventing the sprocket from sliding all the way back?